Mt. Pinatubo, Philippines

The June 12, 1991, eruption of Mt. Pinatubo was rated a VEI 6--10 times larger than the Mt. St. Helens eruption in 1980--and sent a giant ash cloud more than 100,000 feet in the air. Typhoon Yunya also struck the country the same day, and the mix of rain and ash caused major avalanches of mud,...

The June 12, 1991, eruption of Mt. Pinatubo was rated a VEI 6--10 times larger than the Mt. St. Helens eruption in 1980--and sent a giant ash cloud more than 100,000 feet in the air. Typhoon Yunya also struck the country the same day, and the mix of rain and ash caused major avalanches of mud,... (Arlan Naeg / AFP/Getty Images)

The June 12, 1991, eruption of Mt. Pinatubo was rated a VEI 6--10 times larger than the Mt. St. Helens eruption in 1980--and sent a giant ash cloud more than 100,000 feet in the air. Typhoon Yunya also struck the country the same day, and the mix of rain and ash caused major avalanches of mud,...Arlan Naeg / AFP/Getty Images